As a British English speaker I am hesitant about getting involved in
a discussion on schwa in American English but the two languages
are still similar enough for me to dare to intervene.
No-one seems to have mentioned stress so far. In "cactus",
"abacus", "syllabus","phosphorous" (N), and "opus" the schwa
syllables are all unstressed. The invented word "cactusia" like the
more or less real medical words ending in "'-ia" and "-ic" would in
my view be stressed on the penultimate syllable as in "amnesia"
and "ambrosia" (sorry but I couldn't think of any words ending in "-
usia") which would prevent schwa-ing.
This raises another point. Presumably the first vowel of "ambrosia"
would never be schwa-d but what about "amnesia" ? Could the "a"
become schwa in certain contexts, eg "He is suffering from
amnesia"? Or does it depend more on the number of consonants
following the vowel, eg "ammonia" with schwa but "amnesia"
without?
If you combine stress and the number of consonants, do you have
the conditions for an underlying schwa?
Jeremy Whistle
***********************************************************
Jeremy Whistle, School of Business and Management
University College Northampton, Moulton Park, Northampton NN2 7AL, GB
tel: +44 (0)1604 735500 ext: 2182
e-mail: jeremy.whistlenorthampton.ac.uk

(1) There is an ordinary current word 'acalculia' (IPA [ejkalju'lia] or so).
(2) The underlying vowel can be coaxed out by asking "What did you
say?" repeatedly until the speaker elongates and stresses all
syllables. Thus 'calculus' will be rendered 'Kal! Kyu! Luss!' or so.
Now suppose that in the speaker's pronunciation 'rabbit' and 'abbot'
rhyme exactly. The stressed forms will be 'Rab! Bit!' and 'Ab! Bot!'
(or 'Ab! But!') probably. But suppose the speaker is entirely
illiterate: now we might expect that the written vowel will lose its
influence and probably he'll say 'Rab! But!' and 'Ab! But!', with the
schwa expressed as IPA inverted-v (the usual stressed version of schwa
in English), I think. What about 'rhythm'? I suppose some speakers
will make the second syllable 'Mm!', others 'Um!' (with IPA
inverted-v); others might utter a central vowel, a stressed schwa.
In Pittsburgh, the plural of 'you' is not 'youse' or 'y'all' but
'y'uns' (contraction of 'you ones' I guess) -- I don't know how it's
correctly spelled since it is seldom written, and in my experience
some speakers will pronounce it stressed as (IPA) [jInz], [jUnz],
[junz], while others use a stressed schwa, which sounds distinct from
IPA inverted-v (at least to my ear). Here again there is not much
influence from a written form. The New York or Philadelphia plural
'youse' is more commonly written, and perhaps for this reason tends
(in my limited experience) to be more often pronounced with IPA [u]
when stressed (although with a schwa or with (IPA) [I] when
unstressed).
And then of course there's the 'er' sound in non-rhotic pronunciations.
- Doug Wilson